I've been putting chopped liver in my stuffing for YEARS and no one has ever noticed. Ever. And I've never thought about putting it in the food processor although I can see where that would help in a pinch. I've found that finely chopped liver just sort of blends in with the bits of bread and mushrooms. And if you don't want to use livers, I think sautéed mushrooms would do sort of the same thing - add a bit of savory punch.